How should the sentence about raising glasses during a toast be completed?

The sentence should be completed with "were raised" because this construction is grammatically correct in the context of discussing an action that has been performed in the past. "Raised" serves as the past participle of the verb "raise," which means to lift something up. In this case, it indicates that the glasses are being lifted as part of a toast.

Using "were raised" communicates that this action occurred, effectively placing it within the passive voice, making clear that the subjects (the glasses) are recipients of the action rather than the doers. The other options do not fit grammatically or contextually. For instance, "were risen" and "were rose" are incorrect forms that do not align with standard verb usage in English. "Arose" is the past tense of "arise," which also does not convey the intended meaning related to the action of lifting glasses in a toast. Thus, "were raised" is the most appropriate completion for the sentence.